SYSTEM AND METHOD FOR CONTROLLING A TRACKING AUTOFOCUS (TAF) SENSOR IN A MACHINE VISUAL INSPECTION SYSTEM

Abstract

Method for controlling the operation of a tracking autofocus (TAF) section (1000) of a machine vision inspection system (100), comprising an imaging section (205), a movable worktable (210) for holding one or more workpieces (20) in a field of view of the imaging section (205), a control section (120), and a graphical user interface (GUI), wherein the imaging section (205) is configured to be movable along a Z-axis and includes a camera system (260) configured to capture an image of a workpiece (20) on the movable worktable (210), and the TAF section operates to automatically adjust a focus position of the imaging section (205) to focus on a Z-height corresponding to a current surface height of the workpiece (20) in the field of view, wherein the method comprises the following steps: (A) Providing the TAF section,comprising a focus sensor (1012) and a motion control section (1014) that responds to a focus signal derived from the focus sensor (1012) to move the imaging section (205), including the camera system (260), to focus the imaging section (205) at a Z-height corresponding to the current surface height when TAF is enabled; (B) providing operations for enabling and disabling TAF, wherein: (B1) the TAF disabling operations comprise a first set of automatic TAF interruption operations that are automatically triggered by user-initiated operations, including changing the Z-height; and (B2) the TAF disabling operations further comprise a second set of automatic TAF interruption operations that are triggered based on,that at least one respective property of the TAF Z-height surface tracking exceeds a previously set TAF deactivation limit for the respective property of the TAF Z-height surface tracking, are automatically triggered, wherein the property of the TAF Z-height surface tracking that exceeds the previously set TAF deactivation limit corresponds to the abrupt crossing of at least one Z-height discontinuity or an edge on the workpiece (20) by the field of view of the imaging section.

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